With the basics out of the way, we'll now look in more detail at the elements used to provide structure and meaning to the different parts of a form.
| Prerequisites: | A basic understanding of HTML. |
|---|---|
| Objective: | To understand how to structure HTML forms and give them semantics so they are usable and accessible. |
The flexibility of forms makes them one of the most complex structures in HTML; you can build any kind of basic form using dedicated form elements and attributes. Using the correct structure when building an HTML form will help ensure that the form is both usable and accessible.
We already met this in the previous article.
Warning: It's strictly forbidden to nest a form inside another form. Nesting can cause forms to behave unpredictably, so it is a bad idea.
It's always possible to use a form control outside of a element. If you do so, by default that control has nothing to do with any form unless you associate it with a form using its form attribute. This was introduced to let you explicitly bind a control with a form even if it is not nested inside it.
Let's move forward and cover the structural elements you'll find nested in a form.
Many assistive technologies will use the element as if it is a part of the label of each control inside the corresponding element. For example, some screen readers such as Jaws and NVDA will speak the legend's content before speaking the label of each control.
Here is a little example:
form> fieldset> legend>Fruit juice sizelegend> p> input type="radio" name="size" id="size_1" value="small" /> label for="size_1">Smalllabel> p> p> input type="radio" name="size" id="size_2" value="medium" /> label for="size_2">Mediumlabel> p> p> input type="radio" name="size" id="size_3" value="large" /> label for="size_3">Largelabel> p> fieldset> form>
Note: You can find this example in fieldset-legend.html (see it live also).
When reading the above form, a screen reader will speak "Fruit juice size small" for the first widget, "Fruit juice size medium" for the second, and "Fruit juice size large" for the third.
label for="name">Name:label> input type="text" id="name" name="user_name" />
With the associated correctly with the via its for attribute (which contains the element's id attribute), a screen reader will read out something like "Name, edit text".
There is another way to associate a form control with a label — nest the form control within the , implicitly associating it.
label for="name"> Name: input type="text" id="name" name="user_name" /> label>
Even in such cases however, it is considered best practice to set the for attribute to ensure all assistive technologies understand the relationship between label and widget.
If there is no label, or if the form control is neither implicitly nor explicitly associated with a label, a screen reader will read out something like "Edit text blank", which isn't very helpful at all.
Another advantage of properly set up labels is that you can click or tap the label to activate the corresponding widget. This is useful for controls like text inputs, where you can click the label as well as the input to focus it, but it is especially useful for radio buttons and checkboxes — the hit area of such a control can be very small, so it is useful to make it as easy to activate as possible.
For example, clicking on the "I like cherry" label text in the example below will toggle the selected state of the taste_cherry checkbox:
form> p> input type="checkbox" id="taste_1" name="taste_cherry" value="cherry" /> label for="taste_1">I like cherrylabel> p> p> input type="checkbox" id="taste_2" name="taste_banana" value="banana" /> label for="taste_2">I like bananalabel> p> form>
Note: You can find this example in checkbox-label.html (see it live also).
Strictly speaking, you can put multiple labels on a single widget, but this is not a good idea as some assistive technologies can have trouble handling them. In the case of multiple labels, you should nest a widget and its labels inside a single element.
Let's consider this example:
p>Required fields are followed by span aria-label="required">*span>.p> div> label for="username">Name: span aria-label="required">*span>label> input id="username" type="text" name="username" required /> div>
The paragraph at the top states a rule for required elements. The rule must be included before it is used so that sighted users and users of assistive technologies such as screen readers can learn what it means before they encounter a required element. While this helps inform users what an asterisk means, it can not be relied upon. A screen reader will speak an asterisk as "star" when encountered. When hovered by a sighted mouse user, "required" should appear, which is achieved by use of the title attribute. Titles being read aloud depends on the screen reader's settings, so it is more reliable to also include the aria-label attribute, which is always read by screen readers.
The above variants increase in effectiveness as you go through them:
Note: You might get slightly different results, depending on your screen reader. This was tested in VoiceOver (and NVDA behaves similarly). We'd love to hear about your experiences too.
Note: You can find this example on GitHub as required-labels.html (see it live also). Don't test the example with 2 or 3 of the versions uncommented — screen readers will definitely get confused if you have multiple labels AND multiple inputs with the same ID!
Beyond the structures specific to web forms, it's good to remember that form markup is just HTML. This means that you can use all the power of HTML to structure a web form.
Above all, it is up to you to find a comfortable coding style that results in accessible, usable forms. Each separate section of functionality should be contained in a separate element, with elements to contain radio buttons.
Let's put these ideas into practice and build a slightly more involved form — a payment form. This form will contain a number of control types that you may not yet understand. Don't worry about this for now; you'll find out how they work in the next article (Basic native form controls). For now, read the descriptions carefully as you follow the below instructions, and start to form an appreciation of which wrapper elements we are using to structure the form, and why.
form>
h1>Payment formh1> p> Required fields are followed by strong>span aria-label="required">*span>strong>. p>
section> h2>Contact informationh2> fieldset> legend>Titlelegend> ul> li> label for="title_1"> input type="radio" id="title_1" name="title" value="A" /> Ace label> li> li> label for="title_2"> input type="radio" id="title_2" name="title" value="K" /> King label> li> li> label for="title_3"> input type="radio" id="title_3" name="title" value="Q" /> Queen label> li> ul> fieldset> p> label for="name"> span>Name: span> strong>span aria-label="required">*span>strong> label> input type="text" id="name" name="username" required /> p> p> label for="mail"> span>Email: span> strong>span aria-label="required">*span>strong> label> input type="email" id="mail" name="usermail" required /> p> p> label for="pwd"> span>Password: span> strong>span aria-label="required">*span>strong> label> input type="password" id="pwd" name="password" required /> p> section>
section> h2>Payment informationh2> p> label for="card"> span>Card type:span> label> select id="card" name="usercard"> option value="visa">Visaoption> option value="mc">Mastercardoption> option value="amex">American Expressoption> select> p> p> label for="number"> span>Card number:span> strong>span aria-label="required">*span>strong> label> input type="tel" id="number" name="cardnumber" required /> p> p> label for="expiration"> span>Expiration date:span> strong>span aria-label="required">*span>strong> label> input type="text" id="expiration" name="expiration" required placeholder="MM/YY" pattern="^(0[1-9]|1[0-2])\/([0-9])$" /> p> section>
section> p> button type="submit">Validate the paymentbutton> p> section>
form>
h1 margin-top: 0; > ul margin: 0; padding: 0; list-style: none; > form margin: 0 auto; width: 400px; padding: 1em; border: 1px solid #ccc; border-radius: 1em; > div + div margin-top: 1em; > label span display: inline-block; text-align: right; > input, textarea font: 1em sans-serif; width: 250px; box-sizing: border-box; border: 1px solid #999; > input[type="checkbox"], input[type="radio"] width: auto; border: none; > input:focus, textarea:focus border-color: #000; > textarea vertical-align: top; height: 5em; resize: vertical; > fieldset width: 250px; box-sizing: border-box; border: 1px solid #999; > button margin: 20px 0 0 0; > label display: inline-block; > p label width: 100%; >
We applied some extra CSS to the finished form below. If you'd like to make changes to the appearance of your form, you can copy styles from the example or visit Styling web forms.
You've reached the end of this article, but can you remember the most important information? You can find a further test to verify that you've retained this information before you move on — see Test your skills: Form structure.
You now have all the knowledge you'll need to properly structure your web forms. We will cover many of the features introduced here in the next few articles, with the next article looking in more detail at using all the different types of form widgets you'll want to use to collect information from your users.